Avian Nephritis Virus (ANV) was isolated in the 1970s and ANV infections are known in chickens and turkeys. ANV exhibits different degrees of pathogenicity in chickens and turkeys and can present as sub-clinical infection, renal damage, growth retardation, or death of the bird.
ANV has been classified as an astrovirus based on its genome-sequence, with the genome of the G4260 isolate (ANV-1) having been cloned and sequenced (Imada T, Yamaguchi S, Mase M, Tsukamoto K, Kubo M, Morooka A. (Avian nephritis virus (ANV) as a new member of the family Astroviridae and construction of infectious ANV cDNA). J Virol. 2000 September; 74(18):8487-93.).
Previous work has identified at least two serotypes of ANV with representative isolates of serotype 1 (ANV-1) (G4260) (AB033998) and serotype 2 (ANV-2) (e.g. M8) (AB046864) exhibiting very low levels of cross-reactivity by indirect immunofluorescence (IIF) tests and serum neutralisation (SN) tests.
ANV is not easy to isolate and virus specific antisera may not cross-react with other antigenically different ANVs when used in immunostaining-based methods. Whilst there has been some use of RT-PCR tests in relation to the detection of ANV, this has been restricted due to limited knowledge in relation to the sequence variability between known ANV isolates and the sequence diversity that underpins the biological diversity of ANV. A lack of knowledge of ANV viruses has restricted the identification of suitable primers which can be used to detect and quantify the amounts of ANV in a sample, using RT-PCR. In view of this, the nature and extent of disease problems caused by antigentically different ANV types have not been defined due to the absence of convenient diagnostic tests for such antigentically difference ANV types.